From b446822b6ae4e8149902a78cdd4a886634ad6321 Mon Sep 17 00:00:00 2001 From: Noah Goldstein Date: Wed, 15 Jun 2022 10:41:29 -0700 Subject: x86: Add bounds `x86_non_temporal_threshold` The lower-bound (16448) and upper-bound (SIZE_MAX / 16) are assumed by memmove-vec-unaligned-erms. The lower-bound is needed because memmove-vec-unaligned-erms unrolls the loop aggressively in the L(large_memset_4x) case. The upper-bound is needed because memmove-vec-unaligned-erms right-shifts the value of `x86_non_temporal_threshold` by LOG_4X_MEMCPY_THRESH (4) which without a bound may overflow. The lack of lower-bound can be a correctness issue. The lack of upper-bound cannot. --- manual/tunables.texi | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'manual') diff --git a/manual/tunables.texi b/manual/tunables.texi index 1482412078..2c076019ae 100644 --- a/manual/tunables.texi +++ b/manual/tunables.texi @@ -47,7 +47,7 @@ glibc.malloc.mxfast: 0x0 (min: 0x0, max: 0xffffffffffffffff) glibc.elision.skip_lock_busy: 3 (min: -2147483648, max: 2147483647) glibc.malloc.top_pad: 0x0 (min: 0x0, max: 0xffffffffffffffff) glibc.cpu.x86_rep_stosb_threshold: 0x800 (min: 0x1, max: 0xffffffffffffffff) -glibc.cpu.x86_non_temporal_threshold: 0xc0000 (min: 0x0, max: 0xffffffffffffffff) +glibc.cpu.x86_non_temporal_threshold: 0xc0000 (min: 0x4040, max: 0x0fffffffffffffff) glibc.cpu.x86_shstk: glibc.cpu.hwcap_mask: 0x6 (min: 0x0, max: 0xffffffffffffffff) glibc.malloc.mmap_max: 0 (min: -2147483648, max: 2147483647) -- cgit v1.2.3-70-g09d2